Pump



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Dec. zo, 1955 Filed March l, 1950 N. G. KLlNG ETAL PUMP 3 Sheets-Sheet lDe@ 20, 1955 N. G. KUNG UA1. 2,727,466

PUMP

Filed March l, 1950 3 Sheets-Sheet 2 l 5/ f' 52 74 9 1` 4 i@ ff@ 66 54e@ L TQ Q ||` IH muuw INVENTORS.

Dec. 20, 1955 Filed March l, 1950 N. G. KLING ET AL PUMP 3 Sheets-Sheet3 United States Patent C) 2,727,466 PUllIP Nelson G. King, Roslyn, andGeorge Gorham, New

York, N. Y., assignors, by mesne assignments, to TechniconInternational, Ltd., a corporation of New York Application March 1,1950, Serial No. 146,956 18 Claims. (Cl. 103-38) This invention relatesto pumps. One object of the invention is to provide a pump fordispensing, with a high degree of accuracy, a predetermined quantity ofliquid during each liquid-dispensing operation of the pump.

Another object of the invention is the provision of a pump of the abovedescribed character with means for measuring accurately the quantity ofliquid dispensed by the pump and for adjusting the pump to dispensevariable predetermined quantities of liquid.

A further object of the invention is to provide a pump in which thecylinder and piston and valve are easily removable and replaceable, forcleaning, sterilizing, or repair, or for changing the pumping capacity.

A yet further object of the invention is generally to provide a pumpwhich is well adapted to be used for pumping small quantities of uidsfor various purposes, for example, but without limitation, for use intitration, for supplying liquids to chromophotographic columns, for useas medical pump, etc.

The above and other objects, features and advantages of the presentinvention will be apparent or will be more fully explained from thefollowing description wherein reference will be made to the accompanyingillustrative drawings.

In the drawings:

Fig. 1 is.a front view of a pump embodying the present invention;

Fig. 2 is a side view thereof;

Fig. 3 is a vertical sectional view, partly in elevation, on the line 33 of Fig. 2;

Fig. 4 is a vertical sectional view, partly in elevation, on the line 44 of Fig. 1;

Fig. 5 is a horizontal sectional view on the line 5 5 of Fig. 2;

Fig. 6 is a horizontal sectional view on the line 6 6 of Fig. 4;

Fig. 7 is a vertical sectional View on the line 7 7 of Fig. 3;

Fig. 8 is a vertical sectional view on the line 8 8 of Fig. l;

Fig. 9 is a horizontal sectional view on the line 9 9 of Fig. 3.

Referring now to the drawings in detail, the pump comprises a frame 10having a part 12 in which the cylinder 14 of the pump is mounted. Moreparticularly, said part 12 of the frame is provided with an opening 16in which cylinder 14 has a removable t, and said cylinder has anenlarged end portion 18 which is supported by the upper dat surface orabutment portion 20 of frame part 12. A piston 21 has a slidingduid-tight fit in said cylinder 14 and is reciprocated therein ashereinafter described. A valve chamber 22 is seated on and has afluid-tight engagement with the upper surface 24 of the cylinder part18. For providing said fluid-tight engagement, surface 24 of cylinderpart 18 and surface 26 of valve chamber 22 are ground and lapped and, ifdesired, a gasket 28 seated in a groove 30 may be provided in cylinderpart 18, and an integral circular rib 32 may be provided on the lowersurface of valve chamber 22 for engaging said gasket to provide afluid-tight seal between the cylinder and the valve chamber.

The valve chamber 22 is provided with a bore 34 in which a valve 36 isslidable in fluid-tight engagement with the wall of said bore (Fig. 8).Said valve has an inlet passage 38 and an outlet passage 40 each adaptedto register with the port 42 in the valve chamber which communicateswith the combined inlet and exhaust opening 44 at the adjacent or upperend of cylinder 14. The outlet passage 40 of the valve also registers,during the dispensing stroke of the pump, with a port 46 in the valvechamber at the inner end of the outlet passage 48 of said valve chamber.A nipple 50 on one end of Valve 36 and a nipple 51 on the outlet passageof valve chamber 22 provides means for connecting exible or othersuitable tubing (not shown) for the passage of liquid from a suitablesource to the pump and from the pump under the control of said valve. Itwill be understood that by connecting a rubber, plastic, or otherllexible tubing to valve nipple 50, the liquid to be pumped may besupplied directly to said valve without interfering with thereciprocation of the valve.

The valve chamber 22 is removably secured in position on cylinder part18, in fluid-tight engagement therewith, by an adjustable clampingmember 54 which is here shown as in the form of a hollow cylinderthrough which the outlet spindle 52 of the valve chamber projects. Saidclamping member is externally screw threaded and is in screw-threadedengagement with an internally screw-threaded bushing 56 secured instationary position in a block 58 and held against turning in said blockin any suitable way as by pins 60 (Fig. 9). Bushing 56 has a smallclearance in block 58 (Fig. 9) and can pivot about the axes of pins 60so that the inner end of clamping member 54 will engage the uppersurface of valve chamber 22 properly. Block 58 is releasably secured tothe shouldered posts or studs 62, the lower ends 63 of which arethreaded into and thereby secured to the part 12 of frame 10. Said postshave upper reduced portions 64 terminated in heads 66, and block 58 hasa pair of openings each provided with a relatively large portion 70.

communicating with a companion relatively smaller portion 72 as clearlyshown iu Fig. 9. Opening portions 70 are large enough to permit blocks58 to be moved clear of the heads 66 of posts 62, while the smallerportions 72 of said openings when engaged with the reduced end portions64 of said studs, as shown in Fig. 9, prevent said disconnectingmovement of said block. It will be understood that by turning the blockin the direction of the arrow shown in Fig. 9, when clamping member 54is partly retracted, to register portions 70 with heads 66 of the posts,block 58 can be easily withdrawn from posts 62, and that when said blockis removed from frame 10 the valve chamber 22 and the cylinder 14 can beremoved from said frame. Also, it will be understood that aftera'cylinder 14 and a companion valve member 22 are mounted in position onframe 10, they may be quickly secured in that position by replacingblock 58 on posts 62, turning said block in a direction opposite to thedirection of the arrow of Fig. 9, and then screwing down the clampingmember 54 into tight engagement with valve chamber 22. Thus it will benoted that block 58 and the parts associated therewith provide a quickdetachable securing means for the cylinder 14 and the companion valvechamber 22. Handles 74 are provided on clamping member 54 for ease inturning the latter.

Valve 36 is provided with an integral stem portion 76 which isoperatively connected to the valve actuating lever 78. Said connectioncomprises a transverse pin iixed to valve stem 76 and engaging the openupper forked end portion 82 of the said lever 78. Transverse pin 80 inengagement with the sides of the forked end portion 82 positions thevalve so that the inner end of passage 38 and the passage 40 of saidvalve will register with the port `42 of the valve chamber, and .willremain in. said registry, during the operation of the pump. It will benoted that when it is desired to remove valve chamber 22, -after'block58 isrdisconnected from posts 62, this can be readily accomplished byreason of the detachable con'- 4nection of-valve stem 76 with the upperforked end of the valve actuating lever 78.

Valve actuating lever 78 is operated by a cam 84 (Fig. 7 fixed to themain rotary shaft 86 which will hereinafter be described infurtherdetail. `It will be observed that Vlever 78 is secured to a shaft88 journalled for turning movement in bearing members releasablyfastened to frame 10. An arm 92 fixed to shaft 88 is provided with a camfollower roller 94 which is engaged by cam 84 and against which it isheld by a torsion spring 96. Gne end 98 of said torsion spring engageslever 78, at one side of the shaft, and the other end 100 of saidtorsion spring engages a fixed part of the frame. Thus it will beobserved that during the rotation of shaft S6 valve 36 is moved to itsiluid outlet position (Fig. 8) by the high point of cam 84 and thatspring 96 is operable to move said valve to its inlet positioncorresponding to the engagement of cam follower roller 94 on arm 92 withthe low point of cam 84. It will be understood however that it is withinthe scope of the present invention to operate valveactuating lever 78positively in both direction.

The piston 21 is reciprocated, during the rotation of shaft 8.6, by themechanism which will now be described. Said mechanism comprises a cam102 fixed to and rotated by shaft 86 and engageable with a cam followerroller 1.04 carried by part 106 of the piston-operating member 108. Asshown more clearly in Fig. 3, cam follower roller 104 is mounted forrotation in part 106 by a pivot pin 11d. The lower end 112 of the piston21 is removably connected to the socket 114 formed as a part of piston-yoperating member 108. A removable screw 116 is .secured in socket 114and engages kthe side of lower end portion 112 ofthe piston in a groove118 in the latter, so that when member 108 is lowered piston 21 movesdownwardly therewith for the intake stroke of the pump. It will be notedhowever that during the fluid-expelling stroke of piston'21, whichoccurs when piston-operating member 108 is raised, the extreme lower endof said end portion 112 of the piston is engaged directly by the innerlower end of socket member 114, whereby the force of valveopcratingmember 108 is applied directly to piston 21. Compression springs 120 areinterposed between the frame and piston-operating member 108 for holdingcam follower roller 104 in engagement with cam 102 .and `for moving saidpiston-operating member 108 in its pistonretracting stroke. As clearlyshown in Fig. 4, the yupper ends of said springs are fitted in sockets122 provided in frame `10 and the lower ends of said springs are.connected to ears Y124 .on .piston-operating member 19.8.. Saidpiston-operating member is guided for rectilinear movement, ashereinafter disclosed, and is held against turning movement by pairs ofbars 126 which ,are secured at their outer ends in frame 10 in anysuitable way` as indicated at 128 (Fig. 5), the inner ends 130 ofthecompanion bars of each pair being in spaced confronting relation forengagement with the opposite flat sides .of ears 124. ofpiston-operating member 108. Saidpistonoperating member is guided in itsrectilinear movement by the guide ring 132 which is mounted in anopening in the frame and slidably engages the outer surface of socket114 at the upper part of said piston-operating member,A and by thedepending sleeve 134 which slidably engages in the sleeve portion l136of a member ,138 which will bemore particularly described presently.Therefore, it will be apparent that the shaft 86 constitutesmeans commonto the operation of the piston as well as to the actuation 0f the valve.

The operating-length of the stroke of piston 21 is adjustable pursuantto one of the features of the present invention, whereby to vary thequantity of liquid dispensed by the pump, without varying the speed ofrotation of shaft 86, and the latter may be driven by a synchronous orother constant-speed motor. For this purpose an adjustable stop deviceis provided to limit the intake stroke of piston 21. As here shown saidadjustable stop device includes a micrometer screw 140 screw-threadedlyengageable in the abovementioned member 138. A ball 141 is fixed in thelower part of piston-operating member 108 in position to engage theupper or inner end of micrometer screw 140 Vfor limiting the downwardmovement of said piston-operating member 108 and thus limiting theintake stroke of piston 21. Provision is made for turning screw 140 byaccurately measurable amounts whereby to accurately predetermine theintake stroke of piston 21. For this purpose screw 140 is connected tothe operating or adjusting mechanism which will now he described.

The mechanism for turning screw 140 comprises the manually operablemember 142 which, as here shown, is in the form of a drum having asuitable scale on its outer peripheral surface as indicated at 144. Thelower edge of said drum is provided with a knurled circumferentialflange 146 for convenience in turning said drum, said knurled portionbeing accessible externally of frame 10 through the opening 148 in thelower part of said frame (Fig. l). A Vernier member 150 is mounted forrotation coaxially with drum 142 and carries a Vernier scale 152 on itsperipheral outer surface complementary to the scale on member 142. Moreparticularly, as moreclearly shown in Fig. 4 the hub 154 of Verniermember 150 is mounted for turning movement around the collar 156 whichis iixed to and rotates with drum 142 coaxially of screw 140. Members142 and 150 are connected by reducing gear mechanism, presently to bedescribed, as a result of which member 150 has a smaller circumferentialmovement than that of member 142. Collar 156 is fastened to a collar 158fixed to and rotatable with screw 140 so that the latter is turned whendrum 142 isturned. A ring gear 160 is fixed on collar 158 and mesheswith gears 162 journalled for rotation on the spindles or pins 164 whichare carried by the-Vernier drum 150. Said gears 162 mesh with aninternal gear 166 carried by the abovementioned member 138 (Figs. 4 and6), said internal ring gear 166 being secured to said member 138 in anysuitable way as by screws 170. It will be understood that whilemicrometer screw 140 is rotatable and thus adjustable longitudinally ofits axis, directly by rotation of manually operated drum 142, theVernier drum 150 operable :by screw 140 through the planetary gearmechanism constituted by gears 160, 162 and 166, provides for accuratemeasurements of the turning of screw 140 of the stop device forpiston-operating member 108 and thus to provideV for .accuratemeasurement of the quantities of liquid dispensed during the operationof the pump. A transparent `dial plateY 172 is provided (Fig, 1) with anindication thereon for the reference mark for the scale on .drum 142.

Although the capacity of pumps of the construction of the presentinvention may be varied between comparatively wide limits, the followingis set forth, without limitation however, as an indication of thequantities of liquid for which a pump heretofore made and embodying thepresent invention was designed to pump. In said pump, the stroke of thepiston is variable from 3/1000 of one inch to 1/0 of one inch, and thebore of cylinder 14 is such that a duid-expelling stroke of piston 21 isoperable to dispense 000 cc. of liquid for each 1A000 of one inch of thelength of said stroke of the piston. Thus, by adjustment of the stopdevice, which comprises the screw 140, the pump, with this diameter ofthe cylinder bore, is adjustable to measure accurately from 1/{1000 cc.of liquid to 3A0 cc. of liquid, to be dispensed upon eachfluid-expelling stroke of the piston, depending upon the position ofsaid screw 140 as determined by the adjustment of drum 142, with the aidof the vernier drum 150. It is to be understood that the dimensions andquantities just referred to are set forth as indicative of the accuracyof the pump of the present invention and of the small quantities ofliquid which the pump is intended primarily to dispsense, during eachrevolution of shaft 86, but it will be understood that this invention isnot limited to the size of the pump although, as indicated, theinvention was primarily made with the purpose in view of providing apump which is particularly well adapted to dispense an accuratelymeasured small quantity of liquid during each fluid-expelling stroke ofthe piston of the pump, the intake and expelling strokes occurringduring one revolution of the shaft 86. In this pump, member 142 makesfour revolutions for one revolution of vernier member 150.

It will be noted that when it is desired to remove cylinder 14, asexplained above, the piston 21 can be removed at the same time providedthat screw 116 is retracted out of engagement with the lower end 112 ofsaid piston, and of course it will be understood that ordinarily piston21 will be thus removed together with its cylinder 14. Said cylinder andsaid piston can be made of any suitable material commensurate with thedesired accuracy of the pump. For example, said piston and cylinder canbe made of metal or of glass or of any other suitable material whichwill not interfere with the accuracy of the pump. With proper grindingand lapping of the inner surface of the cylinder, a good Huid-tight sealis provided between said cylinder and piston, so that piston rings orother fluidpackings are unnecessary.

It should be noted again that the capacity of the pump, that is thequantity of liquid dispensed by the pump in any adjustment of screw 140between its limits of adjustment, can be varied by the provision of thecylinder of the proper bore diameter and a companion piston ofcorresponding diameter, and it will be noted that a group of cylindersand companion pistons can be provided and any one cylinder and acompanion piston of said group can be mounted in frame 10, so thatsubstantially the same pump can be used for dispensing accuratequantities of vliquid within the range of adjustment of the stop deviceand within the range of piston-bore and cylinder diameters. Also it willbe observed that by reason of the provision in the pump of meansdescribed above for enabling the cylinder, its piston and valve chambercarrying its valve to be quickly and easily removed, a feature of thepump resides in the facility for cleaning or sterilizing the pump as maybe necessary or desirable depending upon the use to which the pump isput.

For the sake of completeness of description, it may be noted that shaft86 is journalled for rotation in anti-friction bearings 174 removablyheld in position by retaining nuts 176. Also it will be noted thatbushings 178 on the inner portion of shaft 86 serve to position cam 102on said shaft in relation to the cam follower roller 104 ofpiston-operating member 108.

It will be noted that in the rotation of drum 142 resulting in thelongitudinal movement of screw 140 of the stop device, said drum movesin the direction of the axis of said screw and that gears 162 which meshwith ring gear 166 of the planetary gear mechanism similarly move in adirection parallel to the axis of screw 140 without disengagement ofgears 162 and 166.

It will be understood that while we have shown and described thepresently preferred embodiment of our invention, the latter may beembodied otherwise than as here specifically illustrated or described,and that in the embodiment of the invention here shown or describedvarious changes in the details of construction and in the form andarrangement of parts may be made without departing from the underlyingidea or principles of this invention within the scope of the appendedclaims.

Having thus described our invention, what we claim and desire to secureby Letters Patent, is:

l. In a pump, a supporting frame, a cylinder removably mounted inposition in said frame, a valve chamber for said cylinder, a valveoperable in said chamber for controlling the admission of fluid to saidcylinder and the expulsion of Huid therefrom, means carried by saidframe and having a releasable connection with said valve for operatingthe latter in said chamber, a piston operable in said cylinder fordrawing duid into the latter and expelling the fluid therefrom under thecontrol of said valve, and means carried by said frame and having areleasable operative connection with said piston for actuating thelatter, said last mentioned means including a releasable memberpositioned externally of said supporting frame for direct accessibilitythereto, said removable mounting of said cylinder in the frame and saidreleasable connections between said valve and valve-operating means andbetween said piston and piston-operating means, respectively,constituting means providing for the removal of said cylinder and thecompanion piston from the frame and the replacement thereof of a similarcylinder and companion piston in said frame, and means for releasablysecuring said cylinder in position in said frame.

2. In a pump, a supporting frame, a cylinder removably mounted in saidframe, said cylinder having a port in one end thereof, a valve chamberremovably secured to said end of the cylinder and having a port inregistry with said port of the cylinder, means cooperating with saidframe and accessible externally thereof for engagement with said valvechamber for releasably clamping the latter against said end of thecylinder for said releasable securement of the valve chamber to said endof the cylinder, a valve operable in said chamber for controlling saidport thereof, a piston operable in said cylinder, means for operatingsaid piston, means for actuating said valve, and means common to bothsaid piston-operating means and said valve-actuating means for actuatingsaid valve in timed relation to the operation of said piston, said meanscooperating with said frame being effective to releasably clamp saidcylinder in position when said valve chamber is releasably clamped bysaid cooperating means.

3. In a pump, a supporting frame, a cylinder removably mounted in saidframe and having a combined inlet and exhaust port in one end thereof, avalve chamber removably secured to said end of the cylinder and having aport in registry with said cylinder port and having an outlet port, avalve operable in said chamber and provided with inlet and outletpassages individually regstrable, in the operation of said valve, withsaid first mentioned port of said valve chamber, the outlet passage ofsaid valve being in communication with said outlet port of said chamberwhen it is in registry with said rst mentioned port thereof, meanscooperating with said frame and accessible externally thereof forengagement with said valve chamber for releasably clamping the latteragainst said end of the cylinder for said releasable securement of thevalve chamber to said end of the cylinder, a piston operable in saidcylinder, means for operating said piston, and means operable in timedrelation to said pistonoperating means for actuating said valve.

4, In a pump, a supporting frame, a cylinder remov- I ably mounted insaid frame and having a combined inlet and exhaust port in one endthereof, a valve chamber removably secured to said end of the cylinderand having a port in registry with said cylinder port and having anoutlet port, a valve operable in said chamber and provided with inletand outlet passages individually registrable, in the operation of saidvalve, with said first mentioned port of said valve chamber, the outletpassage of said valve being in communication with said outlet port ofsaid chamber when it is in registry with said first mentioned portthereof, a piston operable in said cylinder and closing the opposite endthereof, means for operating said piston, means operable in timedrelation to said pistonoperating means for actuating said valve, andmeans carried by said frame for releasably clamping said valve chamberand cylinder in position.

H5. ln a pump, a supporting frame, a cylinder removably mounted in saidframe and having a combined inlet and exhaust' port in one end thereof,a valve chamber removably secured to said end of the cylinder and havinga port in registry with said cylinder port and having an outlet port,- avalve operable in said chamber and provided tvith inlet and outletpassages individually registrable, in the operation of said valve, withsaid first men- Lioned port of said valve chamber, the outlet passage ofsaid valve being in communication with said outlet port of said chamberwhen it is in registry with said first mentioned port thereof, saidinlet passage of the valve extending longitudinally thereof andterminating at its inlet end externally of the valve chamber, said valvehaving provision at said inlet end thereof for securement thereto of aflexible fluid supply tube, said valve having a part opposite said inletend thereof positioned externally of said valve chamber in all operatingpositions of the valve, and means releasably operatively connected tosaid last mentioned part of the valve for actuating said valve.

6. ln a pump, a uppcrting frame, a cylinder mounted in said frame andhaving a combined inlet and exhaust port in one end thereof, a valvechamber secured to said end of the cylinder and having a port inregistry with said cylinder port and having an outlet port, a valveoperable in said chamber and provided with inlet and outlet passagesindividually registrable, in the operation of said valve, with saidfirst mentioned port of said valve charnbcr, the outlet passage of saidvaive being in communication with said outlet port ofv said chamber whenit is in registry with said first mentioned port thereof, said inletpassage of the valve extending longitudinally thereof and terminating atits inlet end externally of the valve chamber, said valve havingprovision at said inlet end thereof for the securernent thereto of aflexible duid supply tube, said valve having a part opposite said inletend thereof positioned externaily of said valve chamber in all operatingpositions of the valve, and means operatively connected to said lastmentioned part of the valve for actuating said valve.

7. In a pump, a supporting frame having a part providing an abutment, acylinder supported by said frame and having an external end part at oneend thereof which engages said abutment, said cylinder having a port atsaid end thereof, a valve chamber removably secured to said end of thecylinder and having a port in registry with said port of the cylinder,means for releasably securing said valve chamber in said engagement withthe cylinder, and means carried by and cooperating with said frame andengageable directly with said valve chamber for releasably clamping thelatter against said end of the cylinder for said releasable securementof the valve chamber to said end or the cylinder, and thereby clampingsaid external end part or" the cylinder against said abutment for thereleasable securement of said cylinder on said frame, saidcylinder beingfree of other operative securement to said frame whereby said cylinderand said valve chamber are removable from said frame upon operation ofsaid clamping means to relieve Vthe clamping action thereof upon saidvalve chamber.

8. ln a pump having a cylinder, a piston reciprocable therein, and meansfor reciprocating saidrpiston comprising a membermovable to a proiectedposition for moving said piston in its duid-expulsion stroke and to aretracted no lon in the movement of said piston in its iluiddntakestroke, a variable stop device for limiting the movement of said memberto its retracted positron comprising a stop member adjustably movable tovarious positions longitudinally of the path of said piston-operatingmember, manually operable means movable to various positions for movingsaid stop member to adjust the position thereof, and means including aVernier device operatively connected to said manually Voperable means'and operable thereby to indicate the adjustedy position of said stopmember, said stop member comprising a screw and said Vernier deviceincluding a rotary member and planetary gear mechanism actuated by saidscrew andconnected to said rotary member for turning the latter pursuantto the operationof said'manually operable means, the latter having ascale and said'rotary member having a Vernier scale complementary tosaid rst mentioned scale.

9. in a pump having a cylinder, a piston reciprocable therein, and meansfor reciprocating said piston compris ing a member novable to aprojected position for moving said piston in its duid-expulsion strokeand to a retracted position in the movement of said piston in itsfluid-intake stroke, a variable stop device forY limiting the movementof said member to its retracted position comprising a stop memberadiustably movable to various positions longitudinally of the path ofsaid piston-operating member, manually operable means movable to variouspositions for moving said stop member to adjust the position thereof,and means including a Vernier device operatively connected to saidmanually operable means and operable thereby to indicate the adjustedposition of said stop member, said stop member comprising a screw andsaid Vernier device including a rotary member and planetary gearmechanism actuated by said screw and connected toV sai-:l rotary memberfor turning the latter pursuant to the n operation of said manuallyoperable means, the latter having a scale and said rotary member havingaVernier scale complementary to said first mentioned scale, said manuallyoperable means comprising a rotary member mounted for rotationco-axially with `and in'relation to said rotary member of saidvernierdevice.

l0. in a pump having a cylinder, a piston reciprocable therein, andmeans for reciprocating said piston comprising a member movable to aproiected position for moving said piston in its fluid-expulsion strokeand to retracted position inthe vmovement of said piston in itsfluid-intake stroke, a variable stop device for limiting the movement ofsaid member to its retracted position comprising a rotary screwlongitudinally adjustable, by the turning thereof, to various positionslongitudinally of the path of said operating member,l a stationarymember in which said screw is threaded for said movement thereof, a irstrotary member connected vto said screw for turning the latter, saidrotary member being provided with a scale, a ysecond rotary membermounted for rotation co-axially with said first rotary member landcarried thereby Aand rotatable in relation thereto, said second rotarymember having a scale thereon, andreducing gearing between said screwand said second rotary member whereby the circumferential movement ofthe latter is less than that of said first rotary member for the samelongitudinal movement of said screw.

ll. ln a pump having acylinder, 4a piston reciprocable therein, andmeansfor reciprocating saidpiston ,compris ing a member movable to aprojected Yposition `for moving saidpiston in its huid-expulsionstrokeand tota retracted position in the movement of said piston in itsfluid-intake stroke, a variable stop device for 'limiting the movementof said member to its retracted position comprising a rotary screwlongitudinally adjustable, by the turning thereof, to variousV`positions longitudinally of the path of said operating member, Aastationaryrmember in which said screw is threaded for said movementthereof, a first rotary member connected to said screw foi-turningV thelatter, said rotary member beingrprovided with a scale, asecond rotarymember mounted for rotation covaxially with said first rotary member andcarried thereby and rotatable rin relation thereto, .said secondrotaryrmember having a scale thereon, and reducing, gearingbetween saidscrew and said second vrotary member `whereby the circumferentialmovement ofythe latter is less than that of said first rotary memberforthe same longitudinalmovement of said screw, ,said` reducing gearingcomprising planetary gearing inclu-ding a ring gear carried by saidstationary member, a gear operable by rotation of said screw and gearscarried by said second rotary member and meshing with said ring gear andsaid screw-operated gear.

12. ln a uid pump having a cylinder and a piston reciprocable therein,means for reciprocating said piston comprising a reciproeablepiston-operating member having a part to which one end of said piston isconnected, mechanism for reciprocating said member including a rotarycam operable on said member for moving the piston in its fluid-expulsionstroke and spring means operable on said member for moving the piston inits tluidintake stroke, said member including a second part open at itsopposite sides, a shaft extending through said second part and carryingsaid cam and the latter being operable on said second part between saidopen sides thereof, and adjustable stop means for variably hunting themovement of said member in the fluid-intake stroke of the piston, saidstop means being adjustable by manual means accessible externally of thepump, said stop means when adjusted being in stationary relation withthe pump.

13. ln a fluid pump having a cylinder and a piston reciprocable therein,means for reciprocating said piston comprising a reciprocablepiston-operating member having a part to which one end of said piston isconnected, mechanism for reciprocating said member including a rotarycam operable on said member for moving the piston in its fluid-expulsionstroke and spring means operable on said member for moving the piston inits tluidintake stroke, said member including a second part open at itsopposite sides, a shaft extending through said second part and carryingsaid cam and the latter being operable on said second part between saidopen sides thereof, said cylinder having a combined inlet and outletport at one end thereof, valve means for controlling the admission andexhaust of uid into and from said cylinder through said port, said valvemeans being reciprocable at right angles to the recprocation of saidpiston, and means for reciprocating said valve means in timed relationto the reciprocation of said piston comprising a cam on said shaft and apivoted lever operable by said cam and operatively connected to saidvalve means.

14. In a pump, a frame having an abutment and spaced studs projectingtherefrom, a cylinder releasably supported by said frame and having apart engaging said abutment for holding the cylinder in position, sai-dstuds having outer headed portions and reduced portions adjacent thelatter providing shoulders on said studs spaced inwardly of said headedportion, a block having openings and releasably engaged by said studs insaid openings, said openings having large portions to clear said headedportions and smaller portions through which said headed portions andshoulders cannot pass, said block being held stationary between saidheaded portions and shoulders when the reduced portions of said studsare in said smaller portions of the openings and said block beingturnable to register the large portions of said openings with saidheaded portions or the release of the block, and means adjustablymovable in said block axially of said cylinder for releasably clampingsaid part of the cylinder against said abutment of the frame.

15. In a pump, a frame having an abutment and spaced studs projectingtherefrom, a cylinder releasably supported by said frame and having apart engaging said abutment for holding the cylinder in position, saidstuds having outer headed portions and reduced portions adjacent thelatter providing shoulders on said studs spaced inwardly of said headedportions, a block having openings and releasably engaged by said studsin said openings, said openings having large portions to clear saidheaded portions and smaller portions through which said headed portionsand shoulders cannot pass, said block being held stationary between saidheaded portions and shoulders when the reduced portions of said studsare in said smaller portions of the openings and said block beingturnable to register the large portions of said openings with saidheaded portions for the release of the block, and means adjustablymovable in said block axially of said cylinder for releasably clampingsaid part of the cylinder against said abutment of the frame, meansproviding fluid passage for said cylinder adjacent said clamping partthereof, said clamping means having an opening through which said fluidpassage means extends.

16. ln a uid pump having a cylinder and a piston reciprocable thereinand means for reciprocating said piston in said cylinder includingmechanism for positively moving the piston in its lluid expulsion strokeand spring means for moving the piston in its tluid intake stroke, anadjustable stop device for limiting the movement of the piston in itsfluid intake stroke comprising a stationary member, a screw rotatable inthe latter for longitudinal movement to variably adjust the positionthereof in relation to said piston longitudinally of the lattersmovement, manually operable means for turning said screw for saidadjustment thereof, said manually operable means having a scale forindicating the adjusted position of the screw, and a Vernier memberoperable by said manually operable means and having a scalecomplementary to said first mentioned scale.

17. In a pump having a cylinder, a piston reciprocable therein, andmeans for reciprocating said piston comprising a member movable to aprojected position for moving said piston in its Fluid-expulsion strokeand to a retracted position in the movement of said piston in itsuid-intake stroke, a variable stop device for limiting the movement ofsaid member to its retracted position comprising a stop memberadjustably movable to various positions longitudinally of the path ofsaid piston-operating member, manually operable means movable to variouspositions for moving said stop member to adjust the position thereof,and means including a Vernier device operatively connected to saidmanually operable means and operable thereby to indicate the adjustedposition of said stop member, said Vernier device comprising planetarygear mechanism operatively associated with said stop member.

18. In a pump having a cylinder, a piston reciprocable therein, andmeans for reciprocating said piston comprising a member movable to aprojected position for moving said piston in its huid-expulsion strokeand to a retracted position in the movement of said piston in itshuid-intake stroke, a variable stop device for limiting the movement ofsaid member to its retracted position comprising a stop memberadjustably movable to various positions longitudinally of the path ofsaid piston-operating member, a manually operable rotary memberrotatable to various positions for moving said stop member to adjust theposition thereof, and speed reduction mechanism including a rotarymember mounted for rotation co-axially with said first mentioned rotarymember and in relation thereto operatively connected to said firstmentioned rotary member and said stop device for adjusting the positionof the latter in response to actuation of said rst mentioned rotarymember.

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